The statements in this section merely provide background information related to the present disclosure and may not constitute prior art.
Recently, the automotive industry has been devoting much energy to research and development in order to increase fuel efficiency by reducing the weight of vehicles using downsized engines having increased power.
Along with increasing efficiency of engines, the exhaust manifold, the exhaust pipe, the catalyst, and the like of an engine are maintained at a higher temperature than in the past.
Accordingly, high performance is desired for heat protectors functioning as components to block heat (i.e. heat shields or heat insulators).
Such a heat protector according to the related art is assembled to the upper portion of an exhaust manifold by means of a bracket, and serves to block and dissipate heat radiated through the exhaust manifold from exhaust gas.
Most heat protectors are conveniently fabricated from a steel sheet coated with aluminum (Al). Recently, the use of Al thin films in vehicles has increased because such films are advantageous in terms of lightness and functionality.
Al thin films have characteristic advantages of high thermal conductivity and superior heat dissipation. However, Al thin films are not easily applicable to a complicated manifold shape. Al thin films are disadvantageously subjected to tearing, cracking, and the like while being formed. In addition, Al thin films are ineffective in reducing noise.
In order to reduce such disadvantages, recently, heat protectors have been fabricated by laminating two or more Al thin films, such that the endurance thereof is improved. In addition, a variety of shapes, such as embossments, concave-convex features, waved shapes, and the like, have been added in order to increase the ability of resultant heat protectors to dissipate heat to the air.
Nevertheless, despite such attempts, when heat protectors are formed from such Al thin films by pressing, the operation of shaping the Al thin films still has problems. For example, two or more films may be separated from each other, and heat protectors fabricated in this manner are still vulnerable to vibrations and noise.
That is, the related-art sheet having a simple wave-shaped pattern has a limited ability to provide both a heat-insulating characteristic and a heat-dissipating characteristic. The related-art sheet cannot increase both a heat-blocking characteristic in the initial stage of the operation of the engine and a heat-dissipating characteristic in a high-temperature area.